1. Field of the Invention
The invention relates to a vehicle airbag device provided at a steering wheel of a vehicle. In particular, the invention relates to a vehicle airbag device having: a pad cover that is provided at the center of a steering wheel constituted of a spoke, a rim (ring portion), and a hub to which the rim is connected via the spoke, and that is secured to the hub or to the spoke; an airbag that is disposed, in a folded state, in the pad cover and deploys upon collision of the vehicle by tearing the pad cover and thus restrains a vehicle occupant; and an inflator that is secured to the hub or to the spoke and supplies inflation gas into the airbag upon collision of the vehicle.
2. Description of the Related Art
According to a vehicle airbag device of this kind, upon collision of the vehicle, the airbag tears an end wall of the pad cover on the rear side of the vehicle (the occupant side) and deploys toward the occupant. Thus, if the interval between the rim of the steering wheel and the occupant is small, it is difficult for the airbag to deploy between the air bag and the rim of the steeling wheel.
Japanese Patent Application Publication No. 2001-277974 (JP-A-2001-277974) describes a vehicle airbag device having an airbag constituted of a bag body the outline of which is, in the inflated state of the airbag, generally circular as viewed from the occupant and a flow-control cloth provided in the bag body so as to control the flow of the inflation gas supplied from the inflator to the inside of the bag body. The flow-control cloth is formed so as to facilitate the deployment of the airbag between the rim of the steering wheel and the occupant upon collision of the vehicle.
According to the vehicle airbag device described in JP-A-2001-277974, however, because the folded airbag is disposed at the center portion of the steering wheel and the tear portions of the pad cover are located at the center of the steering wheel, the distance the airbag needs to travel before reaching a target portion between the rim of the steering wheel and the occupant is substantially equal to that in conventional airbag devices, and thus the airbag deployment inevitably takes a certain time, and therefore the airbag may fail to deploy between the rim and the occupant smoothly.